The problem of cleaning from dust and maintaining free from dust surfaces, in particular large surfaces, is known in the art and several attempts have been made to solve it. The problem is felt in particular in the case of apparatus which has large surfaces that must be kept free from dust in order that their reflecting power be not diminished, such as light-collecting surfaces of solar power generators and the like.
Purely mechanical means for treating surfaces, by air jet or by mechanical cleaning devices, are inefficient and expensive, as they require a considerable amount of energy and their effect is not permanent, so that their application must be continuously renewed. Some attempts have been made to increase the efficiency of dust-removing apparatus by electrical means.
For instance, Russian patent SU 1640666 discloses a method of dust removal from dielectric films which comprises charging the film, passing it through a high voltage DC-charger, cleaning it by air jets providing both blasting and suction, and neutralizing it. This method, however, involves a very high energy consumption.
U.S. Pat. No. 4,751,759 discloses a surface-cleaning appliance which has a nozzle having a narrow, slanted, straight slot blowing a flat laminar air jet obliquely onto the surface being cleaned. An ionizer is connected to the air-blowing jet, so that ions are produced from neutralizing electrically loaded dust particles. Once again, this is a high energy consumption device.
Russian patent SU 698494 describes a method of cleaning the surface of laser mirrors, to remove dust particles, by moving above the surface a film, particularly a fluoropolymer film, carrying a static electrical charge. However, fine dust cannot be cleaned by this manner, and only relatively large particles are removed by attraction to the cleaning film, and the cleaning film must be periodically cleaned of dust.
Clearly, none of the prior art methods and devices satisfactorily solves the problem of cleaning large surfaces and keeping them clean, without high consumption of energy.
It is a purpose of this invention to provide such a method and apparatus which permit to remove from surfaces dust particles.
It is another purpose of this invention to provide a method and apparatus that effectively clean surfaces from dust with a limited energy consumption.
It is a further object of the invention to provide such a method and apparatus that permit to clean large surfaces.
It is a still further purpose of this invention to provide such a method and apparatus which do not comprise components that have to be periodically cleaned.
It is a still further purpose of this invention to provide such a method and apparatus which are based on electrical phenomena only.
Other purposes and advantages of this invention will appear as the description proceeds.